Recently, there is increasing a great demand for high-tech plastics, and a variety of polymers with various novel functions have been being developed. Of those, liquid-crystalline resins which are characterized by the configuration of their molecular chains being in parallel with each other and which have optical anisotropy in melt are widely noticed, as having good fluidity and mechanical properties. However, such liquid-crystalline resins could not still be substituents, by themselves, for precision metal parts, since the mechanical properties of the resins alone are not so good. Therefore, it is necessary to develop liquid-crystalline resin compositions with good mechanical properties by adding some fillers with good mechanical properties to liquid-crystalline resins.
For example, known is a technique of adding aluminium borate whiskers, as a filler with good mechanical properties, to liquid-crystalline resins (see, for example, Japanese Patent Application Laid-Open Nos. 3-59067, 4-96965, 4-198256 and 6-220249). However, the known aluminium borate whiskers are problematic in that, when resin compositions comprising them are formed into precision moldings such as optical pickup parts, the precision moldings could not have intended good mechanical properties and could not be good damping parts, and, in addition, the precision moldings often have different mechanical properties and many failed products with poor mechanical properties are produced.